In view of the rapid rise in the consumption of oil products and the untapped reserves of oil shale, there has been increased interest in finding and developing novel and improved methods and apparatus for recovering oil products from raw oil shale.
Methods and apparatus heretofore provided for recovering oil products from raw oil shale have been classified according to heat application as (1) heat transferred through a wall, (2) heat transferred from the combustion in the retort, (3) heat transferred by passing previously heated gases, and (4) heat transferred by introducing hot solids.
A general object of the present invention is to provide a novel and improved method and apparatus for the recovery of oil products from oil bearing materials, particularly oil shale, which has been found to be satisfactory from the standpoint of operability, economics and completeness of recovery.
Another object of the present invention is to provide a novel method and apparatus for the recovery of oil from oil shale characterized by highly effective heat transfer to the raw oil shale and a crushing of the oil shale to a reduced size as well as a satisfactory holding time to allow for a substantially complete recovery while passing rhrough a heated retort chamber.
A further object of the present invention is to provide a novel method of heating a relatively thin layer or body of crushed shale as it is continuously moved by gravity flow over a heated wall surface of an annular flow passage between an inlet and an outlet with the capability of adjusting the heating time as required.
Yet a further object of the present invention is to provide a novel method and apparatus for retorting oil shale characterized by the steps of preheating the raw oil shale, then crushing and moving the shale against gravity flow in a retort chamber by a moving blade, thereby retaining the oil shale in the retort chamber for an adequate holding time for completeness of recovery, and confining the shale to a layer or bed in a narrow, annular, heated passage during continuous flow from an inlet to an outlet.
Still another object of the present invention is to provide a novel method and apparatus for the recovery of oil shale that may be specially adapted for successive retorting and refining on a relatively small scale as a readily portable unit or adapted for larger scale operations.